Plant pests such as thrips, spider mites and whitefly cause considerable damage to various crops such as salad vegetables, cut flowers and ornamental plants, resulting in significant economic loss to growers and higher prices for consumers. Although plant pests may be controlled using chemical pesticides, this is not always possible or desirable. Indeed, the widespread use of chemical pesticides can result in health and environmental problems, and in the appearance of resistant insect varieties.
Alternative methods for plant pest control have been developed, such as the use of natural predators of plant pests. In particular, beneficial insects such as predatory mites are often used in agriculture for biological control of crop pests such as thrips or spider mites. The predatory mites may be applied to the plants manually, via controlled release systems, or via other methods.
Predatory mites also have applications in areas of pest control other than crop protection, such as in the protection of animals, animal products or fabrics/carpets.
Predatory mites are typically reared in mass-rearing systems, wherein the mites are provided with food sources such as spider mites, pollen, insect eggs, or artificial diet compositions. The choice of food source typically depends on the mite species to be reared. For example, Iphiseius degenerans may be mass-reared on castor bean plants (Ricinus communis L.), which provides a continuous supply of pollen on which the mites can develop large populations. Other predatory mites, such as Amblyseius cucumeris are easier to rear in large quantities, but are less efficient for thrips control.
Especially when mites need to be reared on growing plants this increases costs substantially. Therefore, the use of such predatory mites still is relatively expensive compared to the use of chemical pesticides.